A flywheel of this type, which is also known as an “inertia flywheel”, can filter the rotational jerking of the crankshaft which forms the drive shaft, whilst imparting the rotational torque of the crankshaft to the reaction plate of the clutch device.
The flywheel is secured to the drive shaft, whereas the clutch device is pre-fitted on the gear box. However, there is generally an axial positioning tolerance between the engine and the gear box. In other words, the axial distance between the engine and the gear box can vary by several millimeters from one vehicle to another, for the same vehicle model.
In order to take into account these axial tolerances, it is known to fit the flywheel so as to be mobile axially relative to the reaction plate of the clutch device.
It is known, for example, in particular from document FR-A-2,816,908, to fit a grooved section of the flywheel in an element for connection with the reaction plate. For this purpose, the connection element comprises a central aperture provided with radial teeth which are received in the axial grooves.
The axial grooves thus permit transmission of the rotational movement and of the torque to the reaction plate, whilst permitting axial displacement of the grooved section of the flywheel along the entire amplitude of the axial tolerance.
However, an arrangement of this type may give rise to knocking noises between the teeth of the connection element and the grooves, in particular during sudden variations of speed.
In order to solve this problem, document WO-A-2007/000.151 proposes an anti-noise device which comprises means for fitting the flywheel, which is pre-stressed circumferentially, by expansion into grooves in the element for connection to the reaction plate, in order to prevent knocking of the teeth of the element against the grooves.
However, the pre-stressing is carried out by circumferential resilient return means forming damping means which always permit pivoting of the connection element in relation to the flywheel. Thus, even if the impacts are deadened, they are always present.
In addition, an anti-noise device of this type is onerous and complex to produce, since it comprises many parts which are added to the flywheel.
In addition, this device does not make it possible to eliminate substantial circumferential play between the teeth and the grooves, which for example is greater than 1 mm.
In addition, the fitting of a device of this type is problematic because the grooved element and the connection element are not easy to see, or cannot be seen at all, by an operator during the assembly. This can give rise to errors which can prolong the duration of the assembly of the coupling system.